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Classifying Matter:Elements, Compounds, and
Mixtures
Pure SubstancesA sample of matter that has definite
chemical and physical properties.
Elementspure substance that cannot be separated into
simpler substance by physical or chemical means.
CompoundsPure substance composed of two or more
different elements joined by chemical bonds.
Made of elements in a specific ratio that is always the sameHas a chemical formulaCan only be separated by chemical means, not physically
MixturesA combination of two or more pure substances
that are not chemically combined.substances held together by physical forces,
not chemical No chemical change takes place Each item retains its properties
in the mixture They can be separated physically
Chem4kids.com
Mixtures vs. Compounds
http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/elements_com_mix_6.shtml
Mixture Types
MIXTURES MAY BE HOMOGENEOUS OR HETEROGENEOUS
Homogeneous Mixtures
Homogeneous Mixtures:
The prefix: "homo"- indicates the same
Have the same uniform appearance and composition throughout
Solutions
SOLUTIONS are homogeneous mixtures: Example Soda or
Coffee
A solution has two partsThe substance
in the smallest amount and the one that DISSOLVES is called the SOLUTE
The substance in the larger amount is called the SOLVENT - it does the dissolving IN most common instances water is the solvent
Heterogeneous Mixtures:
The prefix: "hetero"- indicates difference A heterogeneous mixture consists of visibly
different substances or phases Two or more parts can be seen
Examples:
PizzaSandwichChex Mix
Can you identify the following?You will be shown a series of photos. Tell if each
photo represents an item composed of an element, compound, or mixture.
Review:An element contains just one type of atom. A compound contains two or more different atoms
joined together. A mixture contains two or more different
substances that are only physically joined together, not chemically.A mixture can contain both elements and compounds.
Element, Compound, or Mixture?
Rocks
Element, Compound, or Mixture?
Rocks
Element, Compound, or Mixture?
Copper
Element, Compound, or Mixture?
Copper
Element, Compound, or Mixture?
Jelly Beans
Element, Compound, or Mixture?
Jelly Beans
Element, Compound, or Mixture?
Table Sugar
Element, Compound, or Mixture?
Table Sugar
Element, Compound, or Mixture?
Diamond
Element, Compound, or Mixture?
Diamond
Element, Compound, or Mixture?
Tea
Element, Compound, or Mixture?
Tea
Element, Compound, or Mixture?
Salt
Element, Compound, or Mixture?
Salt
Element, Compound, or Mixture?
Neon Gas
Element, Compound, or Mixture?
Neon Gas
Element, Compound, or Mixture?
Salad
Element, Compound, or Mixture?
Salad
Element, Compound, or Mixture?
Pure Water
Element, Compound, or Mixture?
Pure Water
Element, Compound, or Mixture?
Aluminum
Element, Compound, or Mixture?
Aluminum
Element, Compound, or Mixture?
Lemonade
Element, Compound, or Mixture?
Lemonade
Element, Compound, or Mixture?
Silver
Element, Compound, or Mixture?
Silver
Element, Compound, or Mixture?
Sand
Element, Compound, or Mixture?
Sand
